Manuel Machado Macedo

info:eu-repo/semantics/publishedVersio

Near-Infrared Time-Series Photometry in the Field of Cygnus OB2 Association I - Rotational Scenario For Candidate Members

In the last decades, the early pre main sequence stellar rotational evolution picture has been constrained by studies targeting different young regions at a variety of ages. Observational studies suggest a mass-rotation dependence, and for some mass ranges a connection between rotation and the presence of a circumstellar disk. Not still fully explored, though, is the role of environmental conditions on the rotational regulation. We investigate the rotational properties of candidate members of the young massive association Cygnus OB2. The Stetson variability index, Lomb-Scargle periodogram, Saunders statistics, string/rope length method, and visual verification of folded light curves were applied to select 1224 periodic variable stars. Completeness and contamination of the periodic sample was derived from Monte Carlo simulations, out of which 894 periods were considered reliable. Our study was considered reasonably complete for periods from 2 to 30 days. The general rotational scenario seen in other young regions is confirmed by Cygnus OB2 period distributions, with disked stars rotating on average slower than non-disked stars. A mass-rotation dependence was also verified, but as in NGC 6530, lower mass stars are rotating on average slower than higher mass stars, with an excess of slow rotators among the lower mass population. The effect of the environment on the rotational properties of the association was investigated by re-analysing the results while taking into account the incident UV radiation arising from O stars in the association. Results compatible with the disk-locking scenario were verified for stars with low UV incidence, but no statistical significant relation between rotation and disk presence was verified for stars with high UV incidence suggesting that massive stars can have an important role on regulating the rotation of nearby low mass stars.Comment: Submitted on December 23, 201

Angiografia por Ressonância Magnética Tridimensional Optimizada por Contraste nas Doenças da Aorta

Objectivos: Avaliar a possibilidade de realizar angiografia de alta resolução com reconstrução tridimensional, com recurso a equipamento de ressonância magnética de 1 Tesla, em doentes com patologia aórtica. Métodos: Efectuaram-se trinta e um exames de ressonâncias magnética em dezassete doentes, após administração, sob a forma de bolus, de gadolinium. Foram adquiridas imagens em spin echo rápido, gradiente echo e angiografia com time-of-flight. Resultados: Todas as aquisições foram bem toleradas e conseguiu-se a opacificação do lumen aórtico, no momento apropriado, em todos os doentes. As sequências angiográficas foram obtidas com respiração suspensa que requereu cerca de 25 segundos por imagem e seis a oito minutos para conseguir uma reconstrução tridimensional. Conclusão: A angiografia aórtica por reconstrução tridimensional é possível com um equipamento de 1 Tesla, com imagens de elevada qualidade e resolução, obtidas em pouco minutos. É possível obter toda a informação facultada pela aquisição em spin echo, convencional ou acelerado, a partir da reconstrução das imagens tridimensionais, afastando assim a necessidade de aquisição, tão incómoda, das imagens spin echo, melhorar a rapidez e diminuir, portanto, o tempo de aquisição, o que se torna relevante em doentes com síndromes aórticos agudos

Angiografia Pulmonar por Ressonância Magnética Tridimensional Optimizada por Contraste no Estudo da Patologia Vascular Pulmonar

OBJECTIVES: To assess the feasibility of performing pulmonary angiography using MRI with contrast enhancement in patients with pulmonary vascular disease. METHODS: We present our experience in ten individuals, two controls and eight patients who underwent the exam after injection of a gadolinium-based contrast agent on a 1 Tesla MR scanner using a time-of-flight sequence and breath-holding during injection of contrast. RESULTS: Pathology in the main pulmonary artery and its major branches was detected easily while resolution at the segmental and subsegmental levels was inadequate. CONCLUSION: Contrast-enhanced magnetic resonance pulmonary angiography is feasible on a 1 Tesla MR scanner for the study of pathology of the main pulmonary artery and its major branches, like massive pulmonary embolism. However its ability to detect and define distal vessel pathology as found in chronic thromboembolic pulmonary hypertension and small pulmonary emboli is limited

Psychosocial Aspects Associated with Pain Perception in Individuals Undergoing Coronary Surgery

Objectivo: Identificar os factores psicossociais que influenciam a percepção da dor pós-operatória em doentes submetidos a cirurgia de revascularização do miocárdio (CRM). Material e Métodos: Estudo exploratório correlacional de 91 doentes (71 homens e 20 mulheres) submetidos a CRM (pontagem aortocoronária) por esternotomia. A idade média era de 63,8 ± 9,6 anos (entre 39 e 84). Foram utilizados os seguintes instrumentos: Escala Analógica Visual às 24, 48 e 96 horas do pós-operatório; Questionário de Caracterização Demográfica; Mental Health Inventory de 5 itens; Percepção de Saúde Geral (SF-36); Escala de Expectativas de Dor; Escala de Percepção de Apoio; Escala de Expectativas de Auto-eficácia; Satisfação com o tratamento, médicos e enfermeiros (American Pain Society Questionnaire) aplicados às 96 horas após a cirurgia. Resultados: Os doentes que apresentaram expectativas elevadas de dor, percepcionaram maior apoio, apresentaram níveis elevados de auto-eficácia para lidar com a dor ou, se pertenciam ao sexo masculino, sentiram menos dor. De igual modo, os doentes que apresentaram melhor saúde mental, percepcionaram a sua saúde como boa e os doentes que expressaram maior satisfação com o tratamento sentiram menos dor. A dor não foi influenciada pela idade, grau de escolaridade ou pela satisfação com a conduta de médicos e enfermeiros. Conclusão: Após as primeiras 48 horas do pós-operatório, a experiência de dor é influenciada por factores psicossociais, em particular pela expectativa de dor, expectativa de auto-eficácia, apoio percebido, percepção da saúde geral, percepção de saúde mental e satisfação com o tratamento para a dor. Perante os resultados, evidencia-se a necessidade de conjugar conhecimentos no sentido de dar respostas mais alargadas e de carácter multidisciplinar no tratamento da dor pós-operatória em CRM devendo, a par de outros aspectos, focar-se na gestão das expectativas dos doentes

Near-infrared time-series photometry in the field of Cygnus OB2 association II. Mapping the variability of candidate members

We present the results of a J, H, and K photometric variability survey of the central 0.78 square degrees of the young OB association Cygnus OB2. We used data observed with the Wide-Field CAMera at the United Kingdom Infrared Telescope in 2007 (spanning 217 days) to investigate the light curves of 5083 low mass candidate members in the association and explore the occurrence and main characteristics of their near-infrared variability. We identified 2529 stars ($\sim$50$\%$ of the sample) with significant variability with time-scales ranging from days to months. We classified the variable stars into the following three groups according to their light curve morphology: periodic variability (1697 stars), occultation variability (124 stars), and other types of variability (726 stars). We verified that the disk-bearing stars in our sample are significantly more variable in the near-infrared than diskless stars, with a steep increase in the disk-fraction among stars with higher variability amplitude. We investigated the trajectories described by variable stars in the color-space and measured slopes for 335 stars describing linear trajectories. Based on the trajectories in the color-space, we inferred that the sample analyzed is composed of a mix of young stars presenting variability due to hot and cold spots, extinction by circumstellar material, and changes in the disk emission in the near-infrared. We contemplated using the use of near-infrared variability to identify disk-bearing stars and verified that 53.4$\%$ of the known disk-bearing stars in our sample could have been identified as such based solely on their variability. We present 18 newly identified disk-bearing stars and 14 eclipsing binary candidates among CygOB2 lower-mass members.Comment: 19 pages, 21 Figure

Left Ventricular Pseudoaneurysm with a Double Oriffice after Myocardial Infarction

Doente do sexo feminino, 78 anos de idade, internada previamente por EAM combinado. A evolução clínica subsequente decorreu sem complicações, tendo alta ao 10.º dia. Cerca de 12 horas depois foi readmitida no Serviço de Urgência, por dor retrosternal prolongada, hipotensa e prostrada. O ECG (Fig. 1) mostrou re-elevação do segmento ST nas derivações anteriores e inferiores, sendo admitida na Unidade de Cuidados Intensivos com o diagnóstico de provável re-enfarte. O Ecocardiograma realizado na admissão revelou função sistólica global comprometida, sendo possível definir um volumoso espaço anecogénico no ápex do ventrículo esquerdo (VE), com solução de continuidade na transição do terço médio/apical da parede inferior (Fig. 2) e uma segunda solução de continuidade na transição do terço médio/apical da parede lateral do VE (Fig. 3). Em ambos os orifícios foi confirmada a presença de fluxo bidireccional por Doppler Pulsado e Cor (Fig. 2), sugerindo a presença de um pseudoaneurisma do VE com duplo orifício de entrada. A doente foi transferida para um centro cirúrgico, onde, após confirmação intra-operatória do pseudoaneurisma com duplo orifício, foi submetida a encerramento do colo com patch de teflon. Teve alta estável, sendo seguida em consulta de Cardiologia desde há cerca de 16 meses, sem eventos

Evidence for Metallicity-Dependant Spin Evolution in the Kepler field

This is the final version. Available from Oxford University Press via the DOI in this recordData availability: The data underlying this paper are available in CDS.A curious rotation period distribution in the Color-Magnitude-Period Diagram (CMPD) of the Kepler field was recently revealed, thanks to data from Gaia and Kepler spacecraft. It was found that redder and brighter stars are spinning slower than the rest of the main sequence. On the theoretical side, it was demonstrated that metallicity should affect the rotational evolution of stars as well as their evolution in the Hertzprung-R\"ussel or Color-Magnitude diagram. In this work we combine this dataset with medium and high resolution spectroscopic metallicities and carefully select main sequence single stars in a given mass range. We show that the structure seen in the CMPD also corresponds to a broad correlation between metallicity and rotation, such that stars with higher metallicity rotate on average more slowly than those with low metallicity. We compare this sample to theoretical rotational evolution models that include a range of different metallicities. They predict a correlation between rotation rate and metallicity that is in the same direction and of about the same magnitude as that observed. Therefore metallicity appears to be a key parameter to explain the observed rotation period distributions. We also discuss a few different ways in which metallicity can affect the observed distribution of rotation period, due to observational biases and age distributions, as well as the effect on stellar wind torques.European Union Horizon 202